1. Field of the Invention
The present invention relates to an IC card system for performing the collation of a personal identification number (PIN) through a plurality of steps in data processing using an IC card.
2. Description of the Related Art
Today, it is the so-called cash-less age, and it is possible to purchase commodities without paying cash, but using cards issued by credit card companies, etc.
Conventionally-available cards include plastic cards, embossed cards and magnetic stripe cards, which are structurally easy to forge and hence raise the problem of unauthorized use.
As a solution to such a problem, it has been proposed to use information-carrying cards, so-called IC cards, which store information such as personal identification numbers.
In such IC cards, a personal identification number (PIN) is used as a key to access internal data, and an externally input PIN is collated with a PIN prestored in the cards and access to the internal data is permitted when they coincide with each other.
Generally, however, only one PIN is used to permit such data access, so that in the case where important data written in an IC card needs to be checked by a plurality of persons, the individual checkers should read out the internal data with the same PIN for the checking operation. This does not make it possible to perform the checking operation in the correct sequence unless the order of the persons to check the data is determined in advance and the flow of the card is monitored according to the order. As a solution to this problem, the internal data of the IC card may be printed out and the print-out may be circulated for the checking operation. With this method, however, the internal data of the IC card is relatively easy to alter.
This is the bottleneck in realizing a firm banking or home banking system, which has recently been proposed as one application of IC cards and executes various types of data processing for, for example, bank transactions, using IC cards. This is because it is difficult to provide a system for performing the responsible checking operation in the individual checking stages, permitting easy alteration of the data and thus significantly deteriorating the reliability and the security of IC cards.